This invention relates to minute change detecting systems operating to provide electrical signals in response to minute physical changes, and more particularly to minute change detecting systems which are adapted to detect minute mechanical changes caused, for instance, by the rotation of a rotary structure, the vibration of a vibrating structure, and the motion, or deformation, of a pressure storing structure due to its pressure change, and to detect the minute changes of light, heat, pressure, concentration, density, etc.
A capacitor is known as a means to convert a physical change such as a mechanical, dimensional change into an electrical change. In principle, a capacitor consists of two conductor plates. The electrostatic capacity between the two conductor plates can be changed by mechanically displacing one of the two conductor plate. Accordingly, if a signal generator operating to change its output signal according to an electrostatic capacity change is combined with a capacitor which changes its electrostatic capacity according to mechanical displacement, it is possible to provide a minute change detecting system which provides an electrical signal corresponding to the amount of mechanical displacement.
Minute change detecting systems of this type have been proposed in the art. However, it cannot be said that they are sufficient, at least, in performance.